A stopper and/or septum is often employed when closing opened portions of containers used to retain chemicals or medical liquids, such as those used in drug delivery applications. As used herein, the terms stopper and septum are used interchangeably. A stopper is usually designed to meet various quality requirements such as closing properties, gas barrier properties, chemical resistance, needling resistance, low reactivity and the like. Typically, to meet these quality requirements, a conventional stopper is made of a rubber having high elastic deformation, such as polyisoprene elastomer. Other types of rubbers used include synthetic rubbers such as butylene rubber and isoprene rubber, thermoplastic styrene elastomers such as SEBS, thermoplastic elastomers mainly comprising polyisobutylene and polybutadiene, and the like.
Such rubber stoppers facilitate entry of a hollow needle, for instance, a syringe, hypodermic needle, or drug delivery needle, often used to pierce through the stopper from an upper surface to a lower surface thereof to withdraw/extract an amount of a chemical or medical liquid from the container. In order for the needle to efficiently extract the required amount of medicament, the stopper has to be designed in a manner to prevent coring or blockage of the inner pathway of the needle. In addition, when medical liquid is kept in the container, the rubber stopper should be properly sealed, chemically pure, and free from migratory plasticizers and other potential allergic ingredients in order to prevent infection or transmission of these impurities to, for example, a patient or another chemical or medical liquid.
While the containers housing the chemical or medical liquid are often sterilized prior to the introduction of chemicals or medical liquids, the stoppers used to close or contain them are not. When a conventional stopper is penetrated by a needle, the puncture provides a potential path for microorganisms, such as viruses and bacteria, and/or contaminants to enter the interior portion of the sterile container, and therefore the container is often regarded as compromised and needs to be discarded. While stoppers can be used for multiple punctures to assess their robustness, they are usually designed to serve as single dose/single use containers when used, for example, in a medical setting. Vaccine vials, for example, are often used only once after immunizing a patient; however, they may contain unused vaccine that can be used to help protect against diseases. Disposal of these containers, often leads to disposal of costly and limited quantities of medicament.
There remains a need for an improved container stopper that provides a hermetically sealed container when a needle is inserted into the container, liquid is withdrawn, and then the needle is withdrawn and also allows for a multi-dose reusable medicament container.